Europhys. Lett.
Volume 65, Number 2, January 2004
Page(s) 172 - 178
Section General
Published online 01 January 2004
Europhys. Lett., 65 (2) , pp. 172-178 (2004)
DOI: 10.1209/epl/i2003-10069-3

Absolute frequency measurements of the D1 lines in $\chem{{}^{39}K}$, $\chem{{}^{85}Rb}$, and $\chem{{}^{87}Rb}$ with ${\sim 0.1}$ $\un{ppb}$ uncertainty

A. Banerjee, D. Das and V. Natarajan

Department of Physics, Indian Institute of Science - Bangalore 560 012, India

(Received 11 August 2003; accepted in final form 7 November 2003)

We report values for the D1-line frequencies with 0.13 $\un{ppb}$ uncertainty in the alkali atoms $\chem{{}^{39}K}$, $\chem{{}^{85}Rb}$, and $\chem{{}^{87}Rb}$. The frequencies are measured using an evacuated ring-cavity resonator whose length is calibrated against a reference laser locked to the D2 line in $\chem{{}^{87}Rb}$. The measured frequencies, along with sub-ppb measurement of the atomic masses reported previously, form important links in a possible high-precision determination of the fine-structure constant using the photon-recoil shift measured in an atom interferometer. We also obtain, with improved precision, the hyperfine-coupling constants in the P1/2 state of these atoms, and the fine-structure interval in the 5P state of $\chem{Rb}$.

06.30.Ft - Time and frequency.
06.20.Jr - Determination of fundamental constants.
32.10.Fn - Fine and hyperfine structure.

© EDP Sciences 2004